Humidifier



Feb. 18, 1941.

. 20 TO BURNER MOTOR 240 w. w. STUART HUMIDIFIER Filed June '7, 1937 CURRENT 26 SUPPLY Patented Feb. 18, 1941 UNITED STATES PATENT OFFICE HUMIDIFI ER William W. Stuart, Des Moines, Iowa Application June 7, 1937, Serial No. 146,721

2 Claims.

The object of my invention is generally to provide a humidifier including a closed evaporator and provided with inlet and outlet openings, which humidifier has means-for directing a con- 5 trolled flow of air over the water in the humidifier.

It is my further purpose .to provide such a humidifier in which the water is subject to relatively high temperature and to the stream of 10 passing air so controlled that the humidifier has a high capacity with a relatively small size. Such a humidifier does not interfere greatly with the movement of air through the system, especially if the evaporator is installed in the combustion 15 chamber of a heating plant. Such a humidifier also provides for air flow through the humidifier whenever the blower is in operation, even though the humidifier is dry, thereby affording a considerable degree of protection against destruction 20 by high temperature.

Another object is to provide a humidifier of such construction that the replacement of parts likely to become worn out may be accomplished at small expense.

25 Another object is to provide a humidifier that can be automatically controlled.

Still a further purpose of my invention is to provide such a humidifier with parts so arranged that much of the deposit, due to hardness of 30 water, may be removed without dismantling the humidifier.

Another object is to provide a humidifier which can be installed in the combustion chamber and will there provide additional heat absorbing sur- 35 face to heat air when that surface is not needed for evaporating water.

With these and other objects in view, my invention consists in the construction, arrangement and combination of the various parts of the 40 device, whereby the objects contemplated are attained, as hereinafter more fully set forth, pointed out in my claims, and illustrated in the accompanying drawing, in which:

Figure 1 is a sectional view of part of a furnace 45 equipped with a humidifier embodying my invention.

Figures 2, 3 and 4 show methods of supplying air to the humidifier; and

Figure 5 is a diagram showing the circuit con- 50. motions of the humidostat, solenoid coil and burner motor.

In the accompanying drawing I have used the reference numeral to indicate generally the combustion chamber of a furnace of the ordinary as warm air type. My humidifier pecularly adapts itself for use with a furnace of this type and can also be used with split systems.

The outer casing of the furnace is indicated at H and between H) and H is a passage l2 forthe air being heated.

My humidifier may be arranged in a great variety of forms, but its practical embodiment involves a pipe I4 preferably projecting into the combustion chamber ID or into some other zone of high temperature, as the space l3 above the combustion chamber l0. At its inner end, the pipe I4 curves upwardly and terminates in a pipe member l6 passing out through the wall of the combustion chamber and to any convenient point from which themoisture discharged will be taken into the air steam of the system. As here illustrated, the discharge end of the pipe I6 is shownconnected with the intake of the blower 23.

At the outer end of the pipe I4 is a clean-out plug 1-8. The outer end of thepipe I4 communicates with an intake pipe l9. Water is supplied from a pipe2ll to the upper end of the pipe I9 through the solenoid valve and a metering valve 2|. Thus water is supplied through the pipe l9 to the pipe l4 and the pocket l5. 25

At 25 is shown a solenoid valve for controlling the flow through the pipe 20. This may be regulated by a humidostat 26 suitably located and adapted to operate for allowing water flow when the system calls for more humidity. 30

It is desirable to insure the travel of a current of air through the pipe [4 over the pocket l5. This is accomplished in the present illustration by extending a pipe 22 from the inside of the chamber I 2 through the wall H to the upper part of the'pipe [9.

There is shown at 23 a blower fan for controlled air circulation, and at 24 a'burner associated with a motor 24a.

It will be obvious that whenever the air at the 40 inlet of the pipe 22 is under pressure, a flow of air will be maintained through the pipe 22, the pipel9, the pipe l4 and the pipe l6, and that this pressure will exist whenever the fan blower 23 is'operating.

A- fiush-out pipe 21 leads from the pipe 20, ahead of the valve 25, to the pipe IS. A control valve28 regulates flow through the flush-out pipe. Between the junction of the pipes l6 and 21 and the outlet endof the pipe I6 is a valve 29.

Assuming that the system is in operation and that the humidostat calls for moisture, water will be supplied to the evaporator, through the valve 25 which has greater capacity than will ever be required, the flow being reduced by adjustment as of the metering valve 2| to such an amount as can be readily vaporized by the heated parts of the evaporator.

One terminal of the solenoid coil 25 (Fig. 5) is connected to one terminal of the humidostat 26. The other terminal of the solenoid coil and the remaining terminal of the humidostat connect with the two terminals of the burner motor 24a. This places the humidostat and solenoid in series with each other, and this combination in parallel with the burner motor 24a.

Thus no water can fiow to the humidifier when the burner is not running and supplying heat to the evaporator.

When the burner shuts down, the fiow of water to the humidifier is stopped, but the overrun of the blower will continue the operation of the humidifier by driving air over the water remaining in the pocket [5.

The times when the burner operates with a satisfied humidostat serve to heat the evaporator for loosening the encrustations due to the hardness of the water and the loosened particles may be flushed from the evaporator occasionally by closing the valve 29, removing the plug l8 and opening the valve 28.

The evaporator provides additional heating surface for heating air passing through it when it is not evaporating water. This air while being heated serves to hold down the temperature of the evaporator.

The use of a closed evaporator permits the installation of the evaporator in a zone of higher temperature than might otherwise be practical, thereby affording greater evaporating capacity for a given area of heat absorbing surface, and the passing of a controlled air stream through the evaporator retards injury to the heated parts especially when no water is being supplied.

The continued passing of air through the evaporator, after the water supply has been cut ofl, increases capacity by accelerating the removal of the water left in the pocket, before the next operating period of the humidifier.

This makes it possible to adjust the metering valve 2| for a greater fiow of water without the possibility of filling the evaporator with water while a recently started fire is bringing the evaporator up to a Working temperature.

On a cold start with the humidostat calling for moisture and the blower which is subject to control of the bonnet thermostat 30 waiting for a rise in bonnet temperature, the evaporator is protected by water flowing into it. Under such conditions it is possible that, before the blower starts, steam may leave the evaporator through both the pipe [6 and the pipe 22, which is not objectionable. When the blower starts, the accumulated moisture is distributed.

' The evaporator may be located in a zone of high temperature and air of any temperature passed through it. If the humidifier be located in a zone of low temperature, its capacity may be increased by passing heated air through it.v

The entire evaporator may be easily and economically removed for repair and replacement, and where the dead end branch is used, it can be easily removed or replaced.

Figures 2, 3 and 4 illustrate different methods of supplying air to the humidifier. In Figure 2 is shown an arrangement in which air is taken from the blower discharge and the air and water vapor discharged at or near the top of the furnace jacket.

Advantage is taken of the fact that the velocity pressure at the discharge of the blower is greater than the static pressure in the jacket. The difference in these two pressures causes a flow of air through the humidifier.

Figure 3 illustrates a method that might be used with a gravity warm air heating system, a small blower being used to take the comparatively dry air in the lower part of the casing, passing it through the humidifier and discharging it at or near the top of the casing. A modification of this form can be used in connection with a steam or hot water boiler, the air being taken from any desirable location and the water vapor discharged through the basement ceiling into the living quarters above.

Where the arrangement in Figure 3 is used, a

simple method of controlling the blower is to connect the blower motor in parallel with the burner motor. Figure 4 shows a possible arrangement not commonly used, but one in which filters are used on the discharge side of the blower. In such an installation, there will be a higher pressure between the blower discharge and the filters than exists inside the casing of the furnace. Again the pressure difference between the inlet and outlet of the humidifier results in a flow of air through the humidifier.

These forms illustrated in Figures 2, 3 and 4 simply'illustrate some of the varieties of adaptations of the basic structure here involved.

.It is my purpose to cover by my claims these and any further modifications which may be properly included within their scope/ I claim as my invention:

1. In a humidifier, a humidifier proper, having a lower portion for holding water and permitting the passage of air and an upper portion connected therewith at one end of the lower portion, said lower portion having a discharge outlet near its other end for flushing purposes, said lower and upper portions being adapted to be projected into a zone of high temperature, a riser pipe extending upwardly from the end of the lower humidifier portion which has the flushing clean out, said riser pipe having a branch adapted for the fiow of air from the air of a heating system, humidostat controlled means for supplying water to the riser pipe, and means 'for supplying water to the upper portion of the humidifier for flushing purposes, and means for drawing air from the humidifier and conducting it to the air of the heating system. I

,2. In a heating system, a combustion chamber, a casing around the chamber, for air to be heated, a humidifier projected through the casing and into the combustion chamber, said humidifier having passages communicating with each other at their inner end in the combustion chamber, and communicating at their outer ends with the interior of said casing for conducting air from the casingto that part of the humidifier in the combustion chamber and then back to the casing, humidostat controlled means for supplying water to the humidifier according to the requirements of the heating system, and means for mechanically forcing a draft of air through thehumidifier.

WILLIAM W. STUART. 

